Back to EveryPatent.com
United States Patent |
5,619,301
|
Suzuki
,   et al.
|
April 8, 1997
|
Detector for detecting focusing state or distance of photographed object
Abstract
In a focusing state or photographed object distance detector, a pair of
distance measuring lenses are arranged in positions symmetrical with
respect to the reference axis of a photographing lens. A pair of
light-receiving element arrays are arranged behind the pair of distance
measuring lenses. A pair of image signals are obtained by controlling
operations of the light-receiving element arrays by CCD control sections.
A conformity degree between these image signals is calculated by an
integral part shifting arithmetic circuit in an element unit of each of
the light-receiving element arrays. An interpolating calculation of the
conformity degree is made by a decimal part arithmetic circuit to provide
a precise conformity degree distribution. When a shifting amount of the
pair of image signals is calculated by a shifting amount arithmetic
circuit, a distribution portion providing a high conformity degree is
greatly weighted by a weighting arithmetic circuit so that the shifting
amount is obtained with high reliability.
Inventors:
|
Suzuki; Akira (Kawasaki, JP);
Saito; Takao (Yokohama, JP)
|
Assignee:
|
Ricoh Company, Ltd. (Tokyo, JP)
|
Appl. No.:
|
632093 |
Filed:
|
April 15, 1996 |
Foreign Application Priority Data
| Dec 31, 1992[JP] | 4-361035 |
| Sep 10, 1993[JP] | 5-248592 |
Current U.S. Class: |
396/114; 396/128 |
Intern'l Class: |
G03B 013/36 |
Field of Search: |
354/400,402,407,408,406
|
References Cited
U.S. Patent Documents
4816861 | Mar., 1989 | Taniguchi et al. | 354/408.
|
5069543 | Dec., 1991 | Kitajima et al.
| |
5113215 | May., 1992 | Nishibe | 354/408.
|
5192860 | Mar., 1993 | Shinohara et al. | 354/407.
|
5381206 | Jan., 1995 | Akashi et al. | 354/402.
|
Foreign Patent Documents |
62-205324 | Sep., 1987 | JP.
| |
63-18312 | Jan., 1988 | JP.
| |
Primary Examiner: Adams; Russell E.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Parent Case Text
This application is a continuation of application Ser. No. 08/174,704,
filed on Dec. 29, 1993, now abandoned.
Claims
What is claimed is:
1. A device for detecting a focusing state and a photographed object
distance, said device comprising:
a pair of light receiving element arrays each offset from an optical axis
and each configured to receive a light beam from a photographed object and
output a respective image information waveform in accordance with a
photographed object distance, each array of said pair comprising,
a plurality of light receiving elements,
said image information waveform comprising a series of image data generated
from said plurality of light receiving elements, and having a deformation
error component;
a first circuit which determines a degree of conformity between said image
data from both arrays of said pair of element arrays;
a second circuit which weights each of said series of image data of said
respective image information waveforms in accordance with said degree of
conformity determined by said first circuit so as to produce respective
corrected image data waveforms, said second circuit weighing a first
subset of said image data having a high conformity degree determined by
said first circuit greater than a second subset of said image data having
a low conformity degree determined by said first circuit, so that said
respective corrected image data waveforms have reduced amounts of said
deformation error contained therein;
a third circuit which detects said focusing state and said photographed
object distance by determining an image shifting amount between said
respective corrected image information waveforms; and
a fourth circuit which adjusts a focus in accordance with an output of said
third circuit.
2. A device according to claim 1, further comprising means for indicating
whether said state and said photographed object distance can be detected
using the image information waveforms respectively outputted from said
pair of light receiving element arrays and wherein said degree of
conformity represents a reliability of image reproducibility.
3. A device according to any of claims 1 or 2, further comprising means for
evaluating said degree of conformity of said image data by comparing
respective inclined parts of said image information waveform.
4. A device for detecting a focusing state and a photographed object
distance, said device comprising:
a pair of light receiving element arrays each offset from an optical axis
and each configured to receive a light beam from a photographed object and
output a respective image information waveform in accordance with a
photographed object distance, each array of said pair of arrays
comprising,
a plurality of light receiving elements, respectively,
each image information waveform comprising a series of image data generated
from said plurality of light receiving elements, and having a deformation
error component;
a first circuit which determines a degree of conformity between the series
of image data from both arrays of said pair of light receiving element
arrays;
a selection circuit which selects from each waveform a subset of image data
having a degree of conformity greater than a predetermined degree and
discards other image data in order to reduce the amount of deformation
error component present in the respective waveforms;
a detection circuit which detects said focusing state and said photographed
object distance by determining an image shifting amount between said image
information waveforms in accordance with an output of said selection
circuit; and
a circuit which adjusts a focus in accordance with an output of said
detection circuit.
5. A device according to claim 4, further comprising means for detecting
whether said focusing state and said photographed object distance are
detected based on said degree of conformity of said image data which
represents a reliability of image reproducibility and based on the image
information waveforms respectively outputted from said pair of light
receiving element arrays.
6. A device according to any of claims 4 or 5, further comprising means for
evaluating said degree of conformity of said image data by comparing
respective inclined parts of said information waveforms.
7. A device for detecting a focusing state and a photographed object
distance, said device comprising:
a pair of light receiving element arrays each an optical axis and each
configured to receive a light beam from a photographed object and output a
respective image information waveform in accordance with a photographed
object distance, each array of said pair of arrays comprising,
a plurality of light receiving elements, wherein
each image information waveform comprising a series of image data generated
from said plurality of light receiving elements, and having a deformation
error component; and
a first circuit which determines a degree of conformity between said series
of image data from both arrays of said pair of light receiving element
arrays,
wherein said degree of conformity is set as a reliable parameter
representing a reliability of image reproducibility and said reliability
is judged by using the reliable parameter to include whether the focusing
state and the photographed object distance are detected by using the light
beam received by said pair of light receiving element arrays.
8. A device according to claim 7, further comprising means for indicating
whether said focusing state and said photographed object distance can be
detected using the image information waveforms respectively outputted from
said pair of light receiving element arrays and wherein said degree of
conformity represents a reliability of image reproducibility.
9. A device according to any one of claims 7 or 8, further comprising means
for evaluating said degree of conformity of said image data by comparing
respective inclined parts of said information waveforms.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement of a detector for detecting
a focusing state or a distance of a photographed object in which a light
beam from the photographed object is received by a pair of light-receiving
element arrays for detecting the focusing state or the distance of the
photographed object, and the focusing state or the distance of the
photographed object is detected by calculating an image shifting amount of
image information in two systems outputted from the pair of
light-receiving element arrays.
2. Description of the Related Art
In the focusing state or photographed object distance detector of this
kind, image information obtained from two light-receiving element arrays
are relatively shifted from each other to detect a discrete shifting
amount having a highest correlation. An interpolating calculation is made
on the basis of the discrete shifting amount. A continuous image shifting
amount is calculated by performing interpolation using this interpolating
calculated value so as to detect the focusing state or the distance of the
photographed object.
In this case, there is a case in which an error in two image information is
caused since an image is deformed by an error in A/D conversion,
aberrations of an automatic focusing optical system, flare, etc. Such an
error in two image information causes an error in image shifting amount.
Accordingly, in the general focusing state or photographed object distance
detector, the focusing state or the distance of the photographed object is
more accurately detected by using various kinds of methods.
For example, in Japanese Patent Application Laying Open (KOKAI) No.
62-205324, two light-receiving element arrays are arranged within a path
of transmitted light in a photographing optical system such that these two
light-receiving element arrays are symmetrically located with respect to a
photographing optical axis. Each of the two light-receiving element arrays
receives each of two symmetrical light beams transmitted through the
photographing optical system. An interpolating calculation is made by
using a correlational value of image signals from these two
light-receiving element arrays and a contrast value of the photographed
object. A reliable interpolating value with respect to a distance between
two images is obtained by this interpolating calculation. Thus, the
focusing state or the distance of the photographed object is detected with
stable accuracy.
Japanese Patent Application Laying Open (KOKAI) No. 63-18312 shows a
technique for detecting a focusing state or a distance of a photographed
object similar to that shown in the above Japanese Patent Application
Laying Open (KOKAI) No. 62-205324. In this technique, light beams are
focused and formed as two images on two light-receiving element arrays
through a photographing optical system. Contrast evaluating amounts are
compared with each other in all ranges of relative displacements (or image
shifts) of these two images. The focusings rate or the photographed object
distance is more accurately detected by using a larger focusing contrast
evaluating amount in calculation of an image shifting amount.
As mentioned above, in the general focusing state or photographed object
distance detector, two image contrasts are used as parameters for
performing a focusing operation, or contrast values are set to parameters
when evaluated results of the image contrasts are judged, thereby
improving a calculating accuracy. However, there is a limit in improvement
of the calculating accuracy using such a method. Accordingly, it is
desirable to improve the calculating accuracy by using another method, or
detect the focusing state or the distance of the photographed object with
high accuracy by using another method.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a detector
for detecting a focusing state or a distance of a photographed object in
which a light beam from the same photographed object is received by a pair
of light-receiving element arrays for detecting the focusing state or the
distance of the photographed object, and an image data portion providing a
high conformity degree of image information in two systems outputted from
these two light-receiving element arrays is preferentially calculated so
that an image data portion having a large error is removed from the image
information and an image shifting amount can be calculated with high
accuracy.
In accordance with a first structure of the present invention, the above
object can be achieved by a focusing state or photographed object distance
detector comprising a pair of light-receiving element arrays for receiving
a light beam from a photographed object to detect a focusing state or a
distance of the photographed object; the focusing state or the distance of
the photographed object being detected by calculating an image shifting
amount of image information in two systems outputted from the pair of
light-receiving element arrays when the light beam is received by the pair
of light-receiving element arrays; and the detector being constructed such
that the image shifting amount of the image information in the two systems
is calculated in the detection of the focusing state or the photographed
object distance by greatly weighting image data providing a high
conformity degree of the image information in the two systems in
comparison with image data providing a conformity degree which is not
high.
In accordance with a second structure of the present invention, the above
object can be also achieved by a focusing state or photographed object
distance detector comprising a pair of light-receiving element arrays for
receiving a light beam from a photographed object to detect a focusing
state or a distance of the photographed object; the focusing state or the
distance of the photographed object being detected by calculating an image
shifting amount of image information in two systems outputted from the
pair of light-receiving element arrays when the light beam is received by
the pair of light-receiving element arrays; and the detector being
constructed such that the image shifting amount of the image information
in the two systems is calculated in the detection of the focusing state or
the photographed object distance by using only image data providing a high
conformity degree of the image information in the two systems.
In accordance with a third structure of the present invention, the
conformity degree of the image information in the two systems in the first
or second structure is set to a reliable parameter representing
reliability of image reproducibility. Further, it is judged by using this
parameter whether the focusing state or the photographed object distance
can be detected or not by using the above image information.
In accordance with a fourth structure of the present invention, a height of
the conformity degree of the image information in the two systems in each
of the first to third structures is evaluated by comparing inclinations of
curves about the image information with each other every point of the
image information.
In the above focusing state or photographed object distance detector, a
light beam from the photographed object is received by each of the
light-receiving element arrays for detecting the focusing state or the
photographed object distance. When the light beam is received by each of
the light-receiving element arrays, the focusing state or the distance of
the photographed object is detected by calculating an image shifting
amount of image information in two systems outputted from the pair of
light-receiving element arrays. The image shifting amount of the image
information in the two systems is calculated in the detection of the
focusing state or the photographed object distance by greatly weighting
image data providing a high conformity degree of the image information in
the two systems in comparison with another image data providing a
conformity degree which is not high.
Thus, when the focusing state or the photographed object distance is
detected, the image shifting amount can be calculated with high accuracy
by removing image data having a large error from the image information. In
another weighting method, the image shifting amount of the image
information in the two systems may be calculated by using only image data
providing a high conformity degree of the image information in the two
systems.
Further, the conformity degree of the image information in the two systems
is set to a reliable parameter representing reliability of image
reproducibility. It is judged on the basis this parameter whether the
focusing state or the photographed object distance can be detected or not
by using the above image information.
In a concrete weighting method, a height of the conformity degree of the
image information in the two systems is evaluated by comparing
inclinations of curves about the image information with each other every
point of the image information.
In the above focusing state or photographed object distance detector, a
light beam from the same photographed object is received by each of the
light-receiving element arrays for detecting the focusing state or the
distance of the photographed object. An image data portion providing a
high conformity degree of the image information in the two systems
outputted from these two light-receiving element arrays is preferentially
calculated so that an image data portion having a large error is removed
from the image information and the image shifting amount can be calculated
with high accuracy.
Further objects and advantages of the present invention will be apparent
from the following description of the preferred embodiments of the present
invention as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the entire construction of a focusing
state or photographed object distance detector in accordance with one
embodiment of the present invention;
FIG. 2 is a typical constructional view showing the construction of a pair
of light-receiving element arrays shown in FIG. 1 in association with
output waveforms of the light-receiving element arrays;
FIG. 3 is a typical constructional view showing the relation between
construction and arrangement of a pair of distance measuring lenses shown
in FIG. 1;
FIG. 4 is a view of image information outputs showing the relation in phase
between left-hand and right-hand image information photoelectrically
outputted from the pair of light-receiving element arrays shown in FIG. 1;
FIG. 5 is a waveform diagram showing a change in conformity degree as an
evaluation function in the focusing state or photographed object distance
detector in accordance with one embodiment of the present invention;
FIG. 6 is a waveform diagram showing the correlation between a conformity
degree and an output waveform of the pair of light-receiving element
arrays shown in FIG. 1;
FIG. 7 is a waveform diagram showing the correlation of output waveforms of
the pair of light-receiving element arrays shown in FIG. 1 in an address
unit;
FIG. 8 is a flow chart showing the operation of an arithmetic circuit
section shown in FIG. 1;
FIG. 9 is a flowchart about processing steps subsequent to the flow chart
shown in FIG. 8;
FIG. 10 is a flow chart about processing steps subsequent to the flow chart
shown in FIG. 9;
FIG. 11 is a flow chart showing detailed processing contents in processing
steps #46 to #53 in the flow chart shown in FIG. 10;
FIG. 12 is a flow chart showing detailed processing contents in processing
steps #54 to #57 in the flow chart shown in FIG. 11;
FIG. 13 is a flow chart showing a subroutine indicative of a detailed
operation for making an interpolating calculation shown in FIG. 10;
FIG. 14 is a flow chart showing one detailed portion of the interpolating
operation of the detector shown in FIG. 13; and
FIG. 15 is a flow chart showing one detailed portion of the interpolating
operation of the detector shown in FIG. 13.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of a detector for detecting a focusing state or a
distance of a photographed object in the present invention will next be
described in detail with reference to the accompanying drawings.
FIG. 1 is a block diagram showing the entire construction of a focusing
state or photographed object distance detector in accordance with one
embodiment of the present invention. As shown in FIG. 1, a pair of
distance measuring lenses 3 and 4 are arranged behind a focal point face
which is located behind a photographing lens 2 directed toward a
photographed object 1. Each of the distance measuring lenses 3 and 4 is
also called an image reforming lens. In a first case, each of the distance
measuring lenses 3 and 4 is arranged within a path of transmitted light in
a photographing optical system as shown in the above-mentioned two
Japanese Laid-Open Patents. In a second case, each of the distance
measuring lenses 3 and 4 is arranged outside the path of transmitted light
in the photographing optical system. In the present invention, the
focusing state or photographed object distance detector can be used in
each of the first and second cases.
In this embodiment, the pair of distance measuring lenses 3 and 4 are
arranged within the path of transmitted light in the photographing optical
system. In this first case, the photographing optical axis of a lens
system is set to a reference line O directed to the photographed object.
In contrast to this, in the second case in which each of the distance
measuring lenses 3 and 4 is arranged outside the path of transmitted light
in the photographing optical system, the photographing optical axis or a
line parallel to this photographing optical axis is set to a reference
line O.
A pair of light-receiving element arrays 5 and 6 are respectively arranged
on focal point faces of the pair of distance measuring lenses 3 and 4 to
detect a focusing state or a distance of a photographed object. The
right-hand light-receiving element array 5 is arranged on the focal point
face of the right-hand distance measuring lens 3. As shown in FIG. 2, for
example, the right-hand light-receiving element array 5 is constructed by
a line sensor in which a plurality of light-receiving elements R.sub.1 to
R.sub.n are composed of charge coupled devices (CCDs) and are aligned with
each other on a face perpendicular to an optical axis of the right-hand
distance measuring lens 3.
The left-hand light-receiving element array 6 is arranged on the focal
point face of the left-hand distance measuring lens 4. As shown in FIG. 2,
for example, the left-hand light-receiving element array 6 is constructed
by a line sensor in which a plurality of light-receiving elements L.sub.1
to L.sub.n are composed of charge coupled devices (CCDs) and are aligned
with each other on a face perpendicular to an optical axis of the
left-hand distance measuring lens 4. This face perpendicular to the
optical axis of the left-hand distance measuring lens 4 is arranged in the
same direction as the right-hand light-receiving element array 5.
The optical axes of the distance measuring lenses 3 and 4 are parallel to
each other and are also parallel to the above reference line O as an
optical axis of the photographing lens 2.
A light beam from the photographed object 1 is incident to the pair of
distance measuring lenses 3 and 4. A light beam for distance measurement
incident to the right-hand distance measuring lens 3 is focused and formed
as an image on the right-hand light-receiving element array 5. A light
beam for distance measurement incident to the left-hand distance measuring
lens 4 is focused and formed as an image on the left-hand light-receiving
element array 6. Thus, two optical images are symmetrically formed with
respect to the reference line O. As shown in FIG. 2, photoelectrically
converted outputs of the light-receiving elements R.sub.1 to R.sub.n and
the light-receiving elements L.sub.1 to L.sub.n respectively have
waveforms having difference phases in accordance with distances of the
photographed object.
Strictly speaking, each of these waveforms is not a continuous waveform,
but is equal to a stepwise waveform corresponding to each of the number of
light-receiving elements R.sub.1 to R.sub.n and the number of
light-receiving elements L.sub.1 to L.sub.n. As shown in FIG. 3, when a
photographed object 1' is located at a finite distance L, a shifting
amount .DELTA.d of optical images is proportional to 1/L. In other words,
if a base length is set to B and a distance between the formed images is
set to f, the optical image shifting amount .DELTA.d is provided as
follows.
.DELTA.d=Bf/L
Accordingly, the two optical images formed by the light-receiving element
arrays 5 and 6 are located in positions shifted by an equal distance
.DELTA.d/2 from the respective optical axes toward the respective
exteriors.
In FIG. 1, CCD control sections 7 and 8 are respectively connected to the
light-receiving element arrays 5 and 6 and control operations of the
light-receiving elements R.sub.1 to R.sub.n and the light-receiving
elements L.sub.1 to L.sub.n. Outputs of the CCD control sections 7 and 8
respectively correspond to the optical images formed by the
light-receiving element arrays 5 and 6. As shown in FIG. 2, the
light-receiving element arrays 5 and 6 respectively output right-hand
image information 5' and left-hand image information 5'.
Thus, in this embodiment, the pair of distance measuring lenses 3, 4 and
the pair of light-receiving element arrays 5, 6 constitute an image
reforming optical system similar to that shown in the above Japanese
Laid-Open Patents.
In the present invention, the focusing state or photographed object
distance detector electrically processes the right-hand image information
5' and the left-hand image information 6' by using a general correlational
shift calculating method. As shown in FIG. 4, a portion or all of the
right-hand image information 5' are relatively shifted from a portion or
all of the left-hand image information 6' in a horizontal direction. In
FIG. 4, reference numeral N designates a relative shifting amount of the
image information. Data indicative of a conformity degree Q of both the
shifted image information 5' and 6' are plotted to calculate an evaluation
function H(N). As shown in FIG. 5, a local minimum value x is
interpolatively estimated from discrete data [o, H(o)], - - - , [k, H(k)],
[k+1, H(K+1)], etc.
As shown in FIG. 6, all or a portion of a region of each of the image
information 5' and 5' is divided into a high conformity degree portion QH
and a low conformity degree portion QL with respect to a conformity degree
between the two image information 5' and 6'. A distance of the
photographed object is calculated by using a large weight with respect to
the high conformity degree portion QH.
For example, the following formula is calculated as a general
constructional example.
.DELTA.T={.SIGMA. (QI.multidot..DELTA.tI)}/{.SIGMA.QI}
In this formula, .DELTA.T is an image shifting amount in entire electric
processing of the two image information 5' and 6'. .DELTA.tI is an image
shifting amount in electric processing every certain portion of the two
image information 5' and 6'. QI is a conformity degree every certain
portion in the two image information 5' and 6'.
The conformity degree QI every certain portion calculated in this
calculating formula is set to a parameter so as to calculate a weighted
mean thereof. The distance of the photographed object is calculated by
using a larger weight with respect to the image shifting amount .DELTA.tI
calculated from image information providing a higher conformity degree.
In this construction, when a certain noise is added to the two image
information 5' and 6', the conformity degree between the two image
information 5' and 6' is reduced in an image information portion including
this noise so that this image information portion is calculated by using a
relatively small (or low) weight. Accordingly, when such a calculating
method is used, the distance of the photographed object is calculated by
using a large weight in a high conformity degree portion between the two
image information 5' and 6', but is calculated by using a small weight
according to a low conformity degree in a low conformity degree portion
between the two image information 5' and 6'. Thus, it is possible to
improve reliability of the image shifting amount .DELTA.T as data in
entire electric processing of the two image information 5' and 6'.
With respect to the conformity degree QI every certain portion, the two
image information 5' and 6' are relatively shifted from each other as
shown in FIG. 6. At this time, a point N=k providing a high conformity
degree of the two image information 5' and 6' is discretely calculated by
using a normal correlational method. At this time, when the two image
information 5' and 6' overlap each other as shown in FIG. 7, conformity
points of image data are compared with each other every two points such as
(L.sub.1, L.sub.2) and (R.sub.1, R.sub.2); (L.sub.2, L.sub.3) and
(R.sub.2, R.sub.3); - - - . In this comparison, the conformity degree is
increased as inclinations of curves of the two image data approach the
same inclination. For example, a high conformity degree is provided when
the inclination of a curve provided by L.sub.1 and L.sub.2 is parallel to
that provided by R.sub.1 and R.sub.2. In this case, the conformity degree
Q is equal to CL/CH when CL and CH are set to inclinations.
The inclination CL is a smaller inclination with respect to inclinations of
L.sub.2 -L.sub.1 and R.sub.2 -R.sub.1 or inclinations of L.sub.3 -L.sub.2
and R.sub.3 -R.sub.2. The inclination CH is a larger inclination with
respect to the inclinations of L.sub.2 -L.sub.1 and R.sub.2 -R.sub.1 or
the inclinations of L.sub.3 -L.sub.2 and R.sub.3 -R.sub.2.
In this formula Q=CL/CH, CL=CH and Q=1 are formed when the two image data
are in conformity with each other. In this case, the two image data
overlap each other. Q approaches zero as the conformity degree between the
two image data is reduced. Q is assumed to be zero when signs of CL and CH
are reverse to each other. In this case, Q is set to a parameter showing
conformity and is ranged from 0 to 1.
As shown in FIG. 7, a point shown by R.sub.1 overlaps a curve shown by
L.sub.1 and L.sub.2 by shifting this point by a distance .DELTA.tI. Since
.DELTA.t=.DELTA.L/C is formed, .DELTA.tI is provided as follows.
.DELTA.tI=(R.sub.1 -L.sub.1)/(L.sub.2 -L.sub.1)
If the following formula,
.DELTA.T={.SIGMA. (QI-.DELTA.tI)}/{.SIGMA.QI}
is calculated by using these .DELTA.tI, QI, etc. every one point of the two
image information, the distance of the photographed object can be
calculated by providing a weight to information at a high conformity
degree point.
FIG. 1 shows a concrete structure for making various kinds of calculations
in the above conceptional explanation. This structure is constructed by
five kinds of arithmetic circuits composed of an integral part shifting
arithmetic circuit 9, a decimal part arithmetic circuit 10, a weighting
arithmetic circuit 11, a shifting amount arithmetic circuit 12 and a
focusing-driving amount arithmetic circuit 13.
An output section of the focusing-driving amount arithmetic circuit 13 is
connected to a focusing-driving control circuit 14. A focusing-driving
lens constituting the photographing lens 2 is moved by an output of this
focusing-driving control circuit 14 such that this focusing-driving lens
is focused to set a focusing state thereof.
Concrete arithmetic procedures of these circuits will next be explained
with reference to flow charts shown in FIGS. 8 to 15.
In an operation of the integral part shifting arithmetic circuit 9, a local
minimum value shown by reference numeral x in FIG. 5 is calculated in a
step #1 shown in FIG. 8. In the following description, step # is briefly
called #. Addresses at a first local minimum x-coordinate P1.sub.X and a
second local minimum x-coordinate P2.sub.X are constructed by values 0 to
24 of 8 bits and are respectively set to zero to calculate the above local
minimum value x. A first local minimum value P1.sub.Y and a second local
minimum value P2.sub.Y are constructed by values 0 to 6120 of 15 bits and
are set to a maximum value 6120.
The first local minimum value P1.sub.Y is a first smallest local minimum
value and the second local minimum value P2.sub.Y is a second smallest
local minimum value. X-coordinates at these local minimum values P1.sub.Y
and P2.sub.Y are respectively set to the first local minimum x-coordinate
P1.sub.X and the second local minimum x-coordinate P2.sub.X.
In the next step #2, a local minimum value F.sub.M evaluated as a minimum
is constructed by values 0 to 6120 of 16 bits and is set to zero. Further,
an evaluated minimum shifting value NM is constructed by values 0 to 24 of
8 bits and is set to zero as a minimum. Further, an up-down vector Ve is
constructed by values 0 (down) and 1 (up) of 16 bits and a value of this
up-down vector Ve is set to one.
This up-down vector Ve corresponds to "1" meaning an up vector when the
value of this up-down vector is increased. The up-down vector Ve
corresponds to "0" meaning a down vector when the value of this up-down
vector is decreased. In the step #2, a shifting amount N is constructed by
values 0 to 24 of 8 bits and is set to 24 as a maximum.
In the next step #3, an evaluated result F is constructed by values 0 to
6120 of 16 bits and is set to zero as a minimum. The counting number of a
counting register C is constructed by values 0 to 24 of 8 bits and is set
to 24 as a maximum.
In the next step #4, an address LN as one address of the left-hand
light-receiving elements L.sub.1 to L.sub.n shown in FIG. 2 is constructed
by values 0 to 36 of 8 bits and is set to 1/2 times the shifting amount N.
In the next step #5, an address RN as one address of the right-hand
light-receiving elements R.sub.1 to R.sub.n shown in FIG. 2 is constructed
by values 0 to 36 of 8 bits and is set to 12+LN-N. In the next step #6,
F=F+.vertline.L(LN)-R(LN).vertline. is calculated. Then, it proceeds to
the next step #7.
In the step #7, the address LN as one address of the light-receiving
elements L.sub.1 to L.sub.n and the address RN as one address of the
light-receiving elements R.sub.1 to R.sub.n are increased by one in a
counting operation. Further, the counting number of the counting register
C is increased by -1. Namely, the counting number of the counting register
C is decreased by one.
In the next step #8, it is judged whether C.ltoreq.0 is formed or not with
respect to the counting register C. When this judgment in the step #8 is
NO, it is returned to the step #6 so that the steps #6 and #7 are again
executed. In contrast to this, when this judgment in the step #8 is YES,
it proceeds to the next step #9.
In this step #9, the evaluated result F is compared with the evaluated
minimum F.sub.M. When F.ltoreq.F.sub.M is formed so that the judgment in
this step #9 is NO, it proceeds to a step #10. In this step 10, it is
judged whether the up-down vector Ve shows "0" or not. When this up-down
vector Ve shows "1" indicating an up vector so that the judgment in this
step #10 is NO, it proceeds to a step #17. In this step #17, the evaluated
minimum F.sub.M is set to the evaluated result F and the evaluated minimum
shifting value NM is set to the shifting amount N.
In contrast to this, when the judgment in the step #10 is YES, the up-down
vector Ve shows "0" meaning a down vector. In this case, it proceeds to a
step #11. In this step #11, the value of the up-down vector Ve is changed
to "1". In the next step #12, it is judged whether P2.sub.Y
.gtoreq.F.sub.M is formed or not in the relation between the second local
minimum value P2.sub.Y and the evaluated minimum F.sub.M.
When this judgment in the step #12 is YES, it proceeds to the next step
#13. In this step #13, the second local minimum value P2.sub.Y is set to
the evaluated minimum F.sub.M and the second local minimum value
x-coordinate P2.sub.X is set to the evaluated minimum shifting value NM.
Then, it proceeds to the next step #14.
In this step #14, it is judged whether P1.sub.Y .gtoreq.P2.sub.Y is formed
or not in the relation between the first local minimum value P1.sub.Y and
the second local minimum value P2.sub.Y. When this judgment in the step
#14 is NO, it proceeds to the step #17 mentioned above. In contrast to
this, when this judgment in the step #14 is YES, it proceeds to the next
step #15. In this step #15, first and second smallest values of each of
the first local minimum value P1.sub.Y and the second local minimum value
P2.sub.Y are stored to a memory.
In the next step #16, x-coordinate values corresponding to these first and
second smallest values are respectively stored to the memory as a first
local minimum x-coordinate P1.sub.X and a second local minimum value
coordinate P2.sub.X.
When the judgment in the above step #12 is NO, the evaluated minimum
F.sub.M is larger than the second local minimum value P2.sub.Y. In this
case, it proceeds to the step #17. In this step #17, the evaluated minimum
F.sub.M is set to the evaluated result F and the evaluated minimum
shifting value NM is set to the shifting amount N.
When the judgment in the above step #9 is YES, the evaluated result F is
equal to or smaller than the evaluated minimum F.sub.M. In this case, it
proceeds to a step #18. In this step #18, the value of the up-down vector
Ve is set to "0" so that the up-down vector Ve is changed to a down
vector. Then, it proceeds to the step #17.
When the steps #1 to #18 are executed as mentioned above, it proceeds to a
step #19 shown in FIG. 9 through a junction point 2 shown in FIG. 8. In
this step #19, the shifting amount N is decreased by one. In other words,
the shifting amount N set to 24 as an address value in the above step #2
shown in FIG. 8 is changed to 23 and it proceeds to the next step #20.
In the step #20, it is judged whether the shifting amount N is negative or
not. When this judgment in the step #20 is NO, it is returned to the above
step #3 shown in FIG. 2 through a junction point 1 so that processings
subsequent to this step #3 are again executed.
In contrast to this, when the judgment in the step #20 is YES, it proceeds
to the next step #21. In this step #21, it is judged whether the first
local minimum x-coordinate P1.sub.X is equal to zero or not. When this
judgment in the step #21 is YES, it proceeds to the next step #22. In this
step #22, a distance measuring disable flag DEF is set to "1" and it
proceeds to the next step #23.
In this step #23, the shifting amount N set to the evaluated minimum
shifting value NM in the step #17 is stepped from 12 by a value of the
first local minimum x-coordinate P1.sub.X equal to an integral value.
Then, it proceeds to the next step #24.
When the judgment in the above step #21 is NO, it proceeds to a step #25.
In this step #25, it is judged whether the value of the first local
minimum value coordinate P1.sub.X is equal to 24 or not. When this
judgment in the step #25 is YES, it proceeds to the step #22. In contrast
to this, when this judgment in the step #25 is NO, it proceeds to a step
#26. In this step #26, the first local minimum value P1.sub.Y is
subtracted from the second local minimum value P2.sub.Y and it proceeds to
the next step #27. In this step #27, it is judged whether the subtracted
value exceeds 32 or not. When this judgment in the step #27 is YES, it
proceeds to the next step #28. In this step #28, the distance measuring
disable flag DEF is set to "0" and it is then returned to the step #23.
An output value of this distance measuring disable flag DEF is set to "1"
when no distance measuring operation can be normally performed, or when
there is a high possibility that no normal calculated results can be
obtained as expected results. In contrast to this, the output value of the
distance measuring disable flag DEF is set to "0" when the distance
measuring operation can be reliably performed.
Namely, the output value of the distance measuring disable flag DEF is set
to "1" when an address at a detected minimum value is equal to an abnormal
value at a terminal point such as 24, 0, etc., or when the difference
between the first local minimum value P1.sub.Y and the second local
minimum value P2.sub.Y is small.
In contrast to this, when the judgment in the step #27 is NO, the second
local minimum value P2.sub.Y is equal to or lower than 32. In this case,
it is returned to the step #22. In this step #22, the distance measuring
disable flag DEF is set to "1".
In the above step #24, it is judged whether or not the shifting amount N
set in the step #23 is equal to or greater than zero. When this judgment
in the step #24 is YES, it proceeds to the next step #29. In this step
#29, an address RN as one address of the light-receiving elements R.sub.1
to R.sub.n is set to a value (N=12-P1.sub.X) set in the above step #23.
Simultaneously, an end address RE of the light-receiving elements R.sub.1
to R.sub.n is stepped and set to 34. Then, it proceeds to the next step
#30.
In this step #30, an address LN as one address of the light-receiving
elements L.sub.1 to L.sub.n is set to zero. Further, an end address LE of
the light-receiving elements L.sub.I to L.sub.n is set to a value obtained
by subtracting the address RN of the light-receiving elements R.sub.1 to
R.sub.n from 34 set in the step #29.
In contrast to this, when the judgment in the above step #24 is NO, it
proceeds to a step #31. In this step #31, the shifting amount N is changed
to an absolute value of the shifting amount N set in the step #23. I n the
next step #32, the address LN of the light-receiving elements L.sub.1 to
L.sub.n is changed to the value set in the step #31. Further, the end
address LE of the light-receiving elements L.sub.1 to L.sub.n is stepped
and set to 34. Then, it proceeds to the next step #33.
In this step #33, the address RN of the light-receiving elements R.sub.1 to
R.sub.n is set to zero. Further, the end address RE of the light-receiving
elements R.sub.1 to R.sub.n is set to a value obtained by subtracting the
address LN of the light-receiving elements L.sub.1 to L.sub.n from 34 set
above.
Operations in the above steps #24 and #29 to #33 are summarized as follows.
Namely, LN is set to an offset value on an L-side and RN is set to an
offset value on an R-side to overlap data of the left-hand light-receiving
elements L.sub.1 to L.sub.n and the right-hand light-receiving elements
R.sub.1 to R.sub.n at a minimum value calculated by an integral part and a
shifting calculation before a decimal part described later is calculated.
Further, RE and LE are set to terminal values to overlap the above data of
the left-hand light-receiving elements L.sub.1 to L.sub.n and the
right-hand light-receiving elements R.sub.1 to R.sub.n.
Namely, R(RN) and L(LN) as first addresses are compared with each other.
The next addresses R(RN+1) and L(LN+1) are then compared with each other.
Similarly, R(RE) and L(RE) as final addresses are compared with each
other. These comparing operations are performed to calculate a decimal
part described later.
The processing operations in the above #1 to #33 are repeatedly executed so
that the operation of the integral part shifting arithmetic circuit 9
shown in FIG. 1 is completed. Thus, it proceeds to the next step #41 shown
in FIG. 10 through a junction point 3 shown in FIG. 9.
In the step #41, a maximum contrast C.sub.MAX is constructed by values 0 to
255 of 8 bits and is set to a minimum value 0. Further, each of a plus
interpolating value AFP and a minus interpolating value AFM is constructed
by values 0 to .+-.255.times.255.times.35 of 24 bits and is set to a
minimum value 0. Further, each of a plus weight QCP and a minus weight QCM
is constructed by values 0 to .+-.255.times.255.times.35 of 24 bits and is
set to a minimum value 0. After such initializing operations have been
performed, it proceeds to the next step #42.
In this step #42, it is judged whether L(LN) <R(RN)<L(LN+1) is formed or
not. When this judgment in the step #42 is YES, it proceeds to the next
step #44.
In contrast to this, when this judgment in the step #42 is NO, it proceeds
to a step #43. In this step #43, it is judged whether
L(LN)>R(RN+1)>L(LN+1) is formed or not. When this judgment in the step #43
is YES, it proceeds to the step #44. In contrast to this, when this
judgment in the step #43 is NO, it proceeds to a step #46 after a step
#45.
In this step #44, a differential output D constructed by values .+-.255 of
8 bits is obtained by a difference in output between each of the
light-receiving elements L.sub.1 to L.sub.n and each of the
light-receiving elements R.sub.1 to R.sub.n. This differential output D is
calculated as R(RN)-L(LN). Further, a first contrast value C.sub.1
constructed by values .+-.255 of 8 bits is calculated as L(LN+1)-L(LN).
Similarly, a second contrast value C.sub.2 constructed by values .+-.255
of 8 bits is calculated as R(RN+1)-R(RN).
After the differential output D, the first contrast value C.sub.1 and the
second contrast value C.sub.2 have been obtained in this step #44, it
proceeds to a step #45. In this step #45, an interpolating calculation is
made. Detailed contents of this interpolating calculation will next be
explained with reference to FIGS. 13 to 15.
The first contrast value C.sub.1 can be set to three values composed of
zero, a positive value and a negative value. In a step #62 shown in FIG.
13, it is judged whether the first contrast value C.sub.1 is equal to
zero, a positive value or a negative value. When C.sub.1 =0 is formed in
this step #62, there is no contrast of an image so that no decimal part
can be calculated in this image contrast portion (but an integral part can
be calculated). Therefore, it proceeds to a returning step #68 so that it
proceeds to the step #46 without making the interpolating calculation in
this contrast portion.
In contrast to this, when the first contrast value C.sub.1 is greater than
zero (C.sub.1 >0) in the step #62, it proceeds to a step #63. In the step
#63, it is judged whether or not the second contrast value C.sub.2 is
greater than zero (C.sub.2 >0). When this judgment in the step #63 is NO,
signs of the first contrast value C.sub.1 and the second contrast value
C.sub.2 are reverse to each other so that no interpolating calculation can
be made in this image contrast portion (but an integral part can be
calculated). Therefore, it proceeds to the returning step #68 so that it
proceeds to the step #46 without making the interpolating calculation in
this contrast portion.
In contrast to this, when the judgment in the step #63 is YES, the signs of
the first contrast value C.sub.1 and the second contrast value C.sub.2 are
equal to each other so that the interpolating calculation can be made.
Therefore, it proceeds to the next step #64. In the step #64, the first
contrast value C.sub.1 and the second contrast value C.sub.2 are compared
with each other. Namely, in this step #64, it is judged whether C.sub.1
.gtoreq.C.sub.2 is formed or not. When this judgment in the step #64 is
YES, it proceeds to a step #65. In this step #65, the plus interpolating
value AFP is set to AFP+DC.sub.2. In the next step #66, the plus weight
QCP is set to QCP+C.sub.1 C.sub.2 and is stored to a memory. Then, it
proceeds to a step #67.
As mentioned above, in the step #64, it is judged whether C.sub.1
.gtoreq.C.sub.2 is formed or not. When this judgment in the step #64 is
NO, processings in steps #70 to #77 shown in FIG. 14 are executed.
As shown in FIG. 14, in the first step #70, a correction value t.sub.1 is
calculated as follows.
t.sub.I =C.sub.1 C.sub.1 /C.sub.2
In the next step #71, a subcorrection value t.sub.0 is calculated as
follows.
t.sub.0 =XD/C.sub.2
X in this formula is a remaining value obtained by the divisional
calculation in the step #70.
In a step #72, T.sub.1 T.sub.0 =t.sub.1 D+t.sub.0 is calculated from the
calculated results of the main correction amount t.sub.1 in the step #70
and the subcorrection amount t.sub.0 in the step #71. In the next step
#73, the plus interpolating value AFP is set to AFP+T.sub.1 T.sub.0 and it
proceeds to the next step #74. In the step #74, t.sub.1 =C.sub.1 C.sub.1
C.sub.2 is calculated. In the next step #75, the subcorrection amount
t.sub.0 is calculated as t.sub.0 =XC.sub.1 /C.sub.2. In this case, X is a
remaining value obtained by the divisional calculation in the step #74.
In the next step #76, T.sub.1 T.sub.0 =t.sub.1 C.sub.1 +t.sub.0 is
calculated from the calculated results of the main correction amount in
the step #74 and the subcorrection amount in the step #75. In the next
step #77, a plus weight QCP is set to QCP+T.sub.1 T.sub.0 and it is
returned to the step #67 in FIG. 13.
In FIG. 13, when the first contrast value C.sub.1 is smaller than zero
(C.sub.1 <0) in the step #62, it proceeds to a step #78. In the step #78,
it is judged whether the second contrast value C.sub.2 is smaller than
zero (C.sub.2 <0). When this judgment in the step #78 is NO, signs of the
first contrast value C.sub.1 and the second contrast value C.sub.2 are
reverse to each other so that no interpolating calculation can be made in
this image contrast portion (but an integral part can be calculated).
Therefore, it proceeds to the returning step #68 so that it proceeds to
the step #46 without making the interpolating calculation in this contrast
portion.
In contrast to this, when the judgment in the step #78 is YES, the signs of
the first contrast value C.sub.1 and the second contrast value C.sub.2 are
equal to each other so that a decimal part can be calculated. Therefore,
it proceeds to the next step #79. In this step #79, the first contrast
value C.sub.1 is compared with the second contrast value C.sub.2. Namely,
in the step #79, it is judged whether C.sub.1 .ltoreq.C.sub.2 is formed or
not. When the judgment in this step #79 is YES, it proceeds to a step #80.
In this step #80, the minus interpolating value AFM is set to
AFM+DC.sub.2. In the next step #81, the minus weight QCM is set to
QCM+C.sub.1 C.sub.2 and is stored to a memory. Then, it proceeds to the
step #67.
As mentioned above, in the step #79, it is judged whether C.sub.1
.ltoreq.C.sub.2 is formed or not. When this judgment in the step #79 is
NO, processings in steps #82 to #89 shown in FIG. 15 are executed.
As shown in FIG. 15, in the first step #82, a main correction value t.sub.1
is calculated as follows.
t.sub.1 =C.sub.1 C.sub.1 /C.sub.2
In the next step #83, a subcorrection value t.sub.0 is calculated as
follows.
t.sub.0 =XD/C.sub.2
X in this formula is a remaining value obtained by the divisional
calculation in the step #82.
In a step #84, T.sub.1 T.sub.0 =t.sub.1 D+t.sub.0 is calculated from the
calculated results of the main correction amount t.sub.1 in the step #82
and the subcorrection amount t.sub.0 i n the step #83. In the next step
#85, the minus interpolating value AFM is set to AFM+T.sub.1 T.sub.0 and
it proceeds to the next step #86. A calculation in this step #86 is
similar to that in the above step #82. In the next step #87, the
subcorrection amount t.sub.0 is calculated as t.sub.0 =XC.sub.1 /C.sub.2.
In this case, X is a remaining value obtained by the divisional
calculation in the step #86.
In the next step #88, T.sub.1 T.sub.0 =t.sub.1 C.sub.1 +t.sub.0 is
calculated from the calculated results of the main correction amount in
the step #86 and the subcorrection amount in the step #87. In the next
step #89, the minus weight QCM is set to QCM+T.sub.1 T.sub.0 and it is
returned to the step #67 in FIG. 13.
In this step #67, it is judged whether C.sub.MAX .gtoreq..vertline.C.sub.1
.vertline. about the maximum contrast C.sub.MAX and the first contrast
value C.sub.1 is formed or not. When this judgment in the step #67 is YES,
it proceeds to the returning step #68. In contrast to this, when this
judgment in the step #67 is NO, the value of the maximum contrast
C.sub.MAX is rewritten to the value of the first contrast C.sub.1 and it
proceeds to the returning step #68.
The above calculations in the steps #71 and #75 shown in FIG. 14 and the
steps #83 and #87 shown in FIG. 15 are made to calculate an accurate
interpolating value in consideration of the remaining value of each of the
divisional results calculated in the above steps #70 and #74 shown in FIG.
14 and the above steps #82 and #86 shown in FIG. 15.
The interpolating calculation in the step #45 shown in FIG. 10 is thus made
with reference to FIGS. 13 to 15 so that it is returned to subsequent
processing steps shown in FIG. 10. After the interpolating calculation in
the step #45 has been completely made, it proceeds to three groups of
sequential steps #46 to #49, #50 to #53, and #54 to #57. These three step
groups will next be described in detail. First, the group of steps #46 to
#49 will be explained with reference to FIG. 11.
In the step #46, it is judged whether L(LN)<(R(RN+1)<L(LN+1) is formed or
not. When this judgment in the step #46 is YES, it proceeds to the next
step #48.
In contrast to this, when the judgment in the step #46 is NO, it proceeds
to a step #47. In this step #47, it is judged whether
L(LN)>R(RN+1)>L(LN+1) is formed or not. When this judgment in the step #47
is YES, it proceeds the step #48. In contrast to this, when this judgment
in the step #47 is NO, it proceeds to a step #50 after a step #49.
In the step #48, a differential output D constructed by values .+-.255 of 8
bits is obtained by a difference in output between each of the
light-receiving elements L.sub.1 to L.sub.n and each of the
light-receiving elements R.sub.1 to R.sub.n and is calculated as
R(RN+1)-L(LN+1). Further, the first contrast value C.sub.1 is calculated
as L(LN+1)-L(LN). Further, the second contrast value C.sub.2 is calculated
as R(RN+1)-R(RN).
After the differential output D, the first contrast value C.sub.1 and the
second contrast value C.sub.2 are obtained in this step #48, it proceeds
to the step #49. In this step #49, an interpolating calculation similar to
that in the above step #45 explained with reference to FIGS. 13 to 15 is
made.
In the step #50 after the step #49, it is judged whether
R(RN)<L(LN)<R(RN+1) is formed or not. When this judgment in the step #50
is YES, it proceeds to the next step #52.
In contrast to this, when the judgment in the step #50 is NO, it proceeds
to a step #51. In this step #51, it is judged whether R(RN)>L(LN) >R(RN+1)
is formed or not. When this judgment in the step #51 is YES, it proceeds
to the step #52. In contrast to this, when the judgment in the step #51 is
NO, it proceeds to a step #54 after a step #53 (see FIG. 12).
In the step #52, a differential output D is obtained by a difference in
output between each of the light-receiving elements L.sub.1 to L.sub.n and
each of the light-receiving elements R.sub.1 to R.sub.n and is calculated
as R(RN)-L(LN). Further, the first contrast value C.sub.1 is calculated as
R(RN+1)-R(RN). Further, the second contrast value C.sub.2 is calculated as
L(LN+1)-L(LN).
After the differential output D, the first contrast value C.sub.1 and the
second contrast value C.sub.2 are obtained in this step #52, it proceeds
to the step #53. In this step #53, an interpolating calculation similar to
that in the above step #45 explained with reference to FIGS. 13 to 15 is
made.
After the interpolating calculation in the step #53 has been made, it
proceeds to the step #54 shown in FIG. 12 through a junction point 4.
In the step #54, it is judged whether R(RN) <L(LN)<R(RN+1) is formed or
not. When this judgment in the step #54 is YES, it proceeds to the next
step #56.
In contrast to this, when the judgment in the step #54 is NO, it proceeds
to a step #55. In this step #55, it is judged whether R(RN)>L(LN) >R(RN+1)
is formed or not. When this judgment in the step #55 is YES, it proceeds
to the step #56. In contrast to this, when the judgment in the step #55 is
NO, it proceeds to a step #58 after a step #57 (see FIG. 10).
In this step #58, an address RN of each of the light-receiving elements
R.sub.1 to R.sub.n and an address LN of each of the light-receiving
elements L.sub.1 to L.sub.n are stepped by one. In the next step #59, it
is judged whether the present address RN of each of the light-receiving
elements R.sub.1 to R.sub.n reaches an end address RE or not. When this
judgment in the step #59 is NO, the processings from the step #42 to the
step #58 are again executed.
In contrast to this, when the judgment in the step #59 is YES,
predetermined steps have been executed from the present address RN to the
end address RE so that it proceeds to a step #50. In this step #60, it is
judged whether the present address LN of each of the light-receiving
elements L.sub.1 to L.sub.n reaches an end address LE or not. When this
judgment in the step #60 is NO, the processings from the step #42 to the
step #58 are again executed.
In contrast to this, when the judgment in the step #60 is YES,
predetermined steps have been executed from the present address LN to the
end address LE so that it proceeds to a step #61.
In this step #61, a final interpolating value AF and a final weight QC are
calculated. The plus interpolating value AFP and the minus interpolating
value AFM are added to each other. Further, the final weight QC is
provided by adding the plus weight QCP and the minus weight QCM to each
other. The final interpolating value AF is provided by dividing the added
interpolating value AFP+AFM by the added weight QC.
The calculated final interpolating value AF and the calculated weight QC
are transmitted to the focusing-driving control circuit 14 so that a
focusing lens as the photographing lens 2 is moved and focused.
As mentioned above, in a focusing state or photographed object distance
detector having a first structure of the present invention, image data
providing a high conformity degree of image information in two systems are
greatly weighted in comparison with image data providing a conformity
degree which is not high. A focusing state or a distance of a photographed
object is detected by calculating an image shifting amount of the image
information in the above two systems. Accordingly, various kinds of
calculated results can be obtained in a state in which data having many
errors in calculations are substantially removed from the image data.
Therefore, a focusing lens can be focused with high accuracy.
In a focusing state or photographed object distance detector having a
second structure of the present invention, an image shifting amount is
calculated by using only image data providing a high conformity degree of
image information in two systems. A focusing state or a distance of a
photographed object is detected by using this calculated image shifting
amount. Accordingly, various kinds of calculations can be made in a state
in which data having many errors in calculations are removed from the
image data. Therefore, the focusing lens can be focused with high
accuracy. Further, the number of calculating steps can be reduced so that
the construction of the detector can be simplified.
In a focusing state or photographed object distance detector having a third
structure of the present invention, a conformity degree of image
information in two systems is set to a reliable parameter representing
reliability of image reproducibility. Then, it is judged by using this
parameter whether a focusing state or a distance of a photographed object
can be detected or not by using the above image information. Accordingly,
this detection can be judged reliably and accurately. Further, it is
possible to suitably judge whether a distance measuring operation can be
performed or not.
In a focusing state or photographed object distance detector having a
fourth structure of the present invention, the height of a conformity
degree of image information in two systems is evaluated by comparing
inclinations of curves about the image information with each other every
point of the image information. Accordingly, a distance measuring
operation can be accurately performed in an entire region of image data.
Many widely different embodiments of the present invention may be
constructed without departing from the spirit and scope of the present
invention. It should be understood that the present invention is not
limited to the specific embodiments described in the specification, except
as defined in the appended claims.
Top